cc -pthread -Wall -Wextra -Werror=implicit-function-declaration pthread/pthread_cleanup_push.c -o pthread/pthread_cleanup_push -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lintl -liconv pthread/pthread_cleanup_push.c: In function ‘start’: pthread/pthread_cleanup_push.c:21:9: error: implicit declaration of function ‘pthread_cleanup_push’ [-Wimplicit-function-declaration] 21 | pthread_cleanup_push(cleanup, NULL); | ^~~~~~~~~~~~~~~~~~~~ pthread/pthread_cleanup_push.c:24:9: error: implicit declaration of function ‘pthread_cleanup_pop’ [-Wimplicit-function-declaration] 24 | pthread_cleanup_pop(0); | ^~~~~~~~~~~~~~~~~~~ pthread/pthread_cleanup_push.c: In function ‘main’: pthread/pthread_cleanup_push.c:36:23: error: implicit declaration of function ‘pthread_cancel’; did you mean ‘pthread_once’? [-Wimplicit-function-declaration] 36 | if ( (errno = pthread_cancel(thread)) ) | ^~~~~~~~~~~~~~ | pthread_once pthread/pthread_cleanup_push.c:41:24: error: ‘PTHREAD_CANCELED’ undeclared (first use in this function); did you mean ‘PTHREAD_NULL’? 41 | if ( result != PTHREAD_CANCELED ) | ^~~~~~~~~~~~~~~~ | PTHREAD_NULL pthread/pthread_cleanup_push.c:41:24: note: each undeclared identifier is reported only once for each function it appears in